21,759 research outputs found

    Liberate your avatar; the revolution will be social networked

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    This paper brings together the practice-based creative research of artists Charlotte Gould and Paul Sermon, culminating in a collaborative interactive installation that investigates new forms of social and political narrative in multi-user virtual environments. The authors' artistic projects deal with the ironies and stereotypes that are found within Second Life in particular. Paul Sermon’s current creative practice looks specifically at the concepts of presence and performance within Second Life and 'first life', and attempts to bridge these two spaces through mixed reality techniques and interfaces. Charlotte Gould’s Ludic Second Life Narrative radically questions the way that users embody themselves in on-line virtual environments and identifies a counter-aesthetic that challenges the conventions of digital realism and consumerism. These research activities and outcomes come together within a collaborative site-specific public installation entitled Urban Intersections for ISEA09, focusing on contested virtual spaces that mirror the social and political history of Belfast. The authors' current collaborative practice critically investigates social, cultural and creative interactions in Second Life. Through these practice-based experiments the authors' argue that an enhanced social and cultural discourse within multi-user virtual environments will inevitably lead to growth, cohesion and public empowerment, and like all social networking platforms, contribute to greater social and political change in first life

    New battery model and state-of-health determination through subspace parameter estimation and state-observer techniques

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    This paper describes a novel adaptive battery model based on a remapped variant of the well-known Randles' lead-acid model. Remapping of the model is shown to allow improved modeling capabilities and accurate estimates of dynamic circuit parameters when used with subspace parameter-estimation techniques. The performance of the proposed methodology is demonstrated by application to batteries for an all-electric personal rapid transit vehicle from the Urban Light TRAnsport (ULTRA) program, which is designated for use at Heathrow Airport, U. K. The advantages of the proposed model over the Randles' circuit are demonstrated by comparisons with alternative observer/estimator techniques, such as the basic Utkin observer and the Kalman estimator. These techniques correctly identify and converge on voltages associated with the battery state-of-charge (SoC), despite erroneous initial conditions, thereby overcoming problems attributed to SoC drift (incurred by Coulomb-counting methods due to overcharging or ambient temperature fluctuations). Observation of these voltages, as well as online monitoring of the degradation of the estimated dynamic model parameters, allows battery aging (state-of-health) to also be assessed and, thereby, cell failure to be predicted. Due to the adaptive nature of the proposed algorithms, the techniques are suitable for applications over a wide range of operating environments, including large ambient temperature variations. Moreover, alternative battery topologies may also be accommodated by the automatic adjustment of the underlying state-space models used in both the parameter-estimation and observer/estimator stages

    Magnetically Stimulated Diffusion of Rydberg Gases

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    The specific kind of diffusion stimulated (rather than suppressed) by the external magnetic field, which was predicted for the first time by Schmelcher and Cederbaum in 1992, is considered here for the case of high-angular-momentum (i.e., approximately "circular") Rydberg atoms. The coefficient of such diffusion was calculated by a purely analytical approach and was found to be well relevant to the experiments on antihydrogen formation.Comment: REVTeX4, 4 pages, 1 EPS figure; v2: additional numerical estimates and extended discussion in the end of pape

    Novel battery model of an all-electric personal rapid transit vehicle to determine state-of-health through subspace parameter estimation and a Kalman Estimator

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    Abstract--The paper describes a real-time adaptive battery model for use in an all-electric Personal Rapid Transit vehicle. Whilst traditionally, circuit-based models for lead-acid batteries centre on the well-known Randles’ model, here the Randles’ model is mapped to an equivalent circuit, demonstrating improved modelling capabilities and more accurate estimates of circuit parameters when used in Subspace parameter estimation techniques. Combined with Kalman Estimator algorithms, these techniques are demonstrated to correctly identify and converge on voltages associated with the battery State-of-Charge, overcoming problems such as SoC drift (incurred by coulomb-counting methods due to over-charging or ambient temperature fluctuations). Online monitoring of the degradation of these estimated parameters allows battery ageing (State-of-Health) to be assessed and, in safety-critical systems, cell failure may be predicted in time to avoid inconvenience to passenger networks. Due to the adaptive nature of the proposed methodology, this system can be implemented over a wide range of operating environments, applications and battery topologies

    Estimating the Economic Impact of Acas Services

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    The main focus of this report is on the economic value of a year of Acas services delivered during the 2014/15 operational year. The starting point for the analysis in this report is the prior review of the economic impact of Acas in 2007 (Meadows), which is based on Acas activities delivered in 2005/06. This has been updated in line with key principles of cost-benefit analysis and tackles a number of issues flagged in subsequent reviews with a particular focus on questions of the counterfactual, impacts beyond the first year of Acas intervention, and of displacement and substitution. In addition, new estimates have been provided in service areas that were not included in the 2007 study as well as in new areas of Acas activity, such as new digital channels of service delivery. Whereas previous economic impact analyses were estimated to account for around 70 per cent of Acas service delivery, this report considers approximately 90 per cent of Acas activitie
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